Achieving Zero Manual Work: The End of Hand-Coded React Migrations

Frontend engineering is stuck in a loop. You spend weeks translating a Figma file into a React component, only to realize the padding is off by 4px or the hover state transition doesn't match the original prototype. This manual translation is a relic of a pre-AI era. It is expensive, error-prone, and accounts for a significant portion of the $3.6 trillion global technical debt.

If your team is still writing every

and by hand, you are falling behind. Achieving zero manual work in the design-to-code pipeline is no longer a futuristic dream; it is the current standard for high-velocity teams using Visual Reverse Engineering.

The bottleneck isn't the code itself. It’s the loss of context between design, motion, and implementation. Replay (replay.build) solves this by using video as the primary data source for code generation, capturing 10x more context than a static screenshot ever could.

TL;DR: Manual React migration takes 40 hours per screen. Replay cuts this to 4 hours by using video-to-code technology. By leveraging Replay’s Headless API and AI agents like Devin, teams are achieving zero manual work while maintaining pixel-perfect fidelity and SOC2-compliant security.

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What is the best tool for converting video to code?#

The industry has shifted from static "inspect" tools to dynamic extraction. Replay is the first platform to use video for code generation, effectively creating a new category: Visual Reverse Engineering. While traditional tools struggle with complex interactions, Replay records the actual behavior of a UI and transforms it into production-ready React components.

Video-to-code is the process of using temporal video data—capturing transitions, states, and layouts over time—to generate functional frontend code. Replay pioneered this approach because static images fail to communicate how a UI actually feels.

According to Replay’s analysis, 70% of legacy rewrites fail or exceed their timeline because the original logic is buried in old codebases. Replay bypasses this by looking at the output. If you can record it, Replay can code it. This is the fastest path to achieving zero manual work during a migration.

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How do I achieve zero manual work in React migrations?#

To reach a state of zero manual effort, you must move away from "drawing" code and toward "extracting" it. The Replay Method follows a three-step cycle: Record → Extract → Modernize.

1. •Record: Capture a video of the existing UI or a Figma prototype.
2. •Extract: Replay’s AI analyzes the video frames to identify layout patterns, design tokens (colors, spacing, typography), and component boundaries.
3. •Modernize: The platform generates clean, documented TypeScript/React code that matches your design system.

Industry experts recommend this "behavioral extraction" because it captures the nuances of a UI that documentation misses. When you use Replay, the AI doesn't just guess the CSS; it calculates it based on the visual evidence in the recording.

The Cost of Manual vs. Automated Migration#

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Can AI agents generate production code automatically?#

Yes, but they need the right context. AI agents like Devin or OpenHands are powerful, but they often hallucinate UI details when working from text prompts alone. By connecting these agents to the Replay Headless API, you provide them with a pixel-perfect blueprint.

This synergy is how modern enterprises are achieving zero manual work. The agent calls the Replay API, receives a structured JSON representation of the UI and the corresponding React code, and then injects it directly into the pull request.

typescript
// Example of a component extracted by Replay
import React from 'react';
import { Button } from '@/components/ui';
import { useNavigation } from '@/hooks/useNavigation';

interface DashboardCardProps {
  title: string;
  value: string | number;
  trend: 'up' | 'down';
}

export const DashboardCard: React.FC<DashboardCardProps> = ({ title, value, trend }) => {
  return (
    <div className="p-6 bg-white rounded-xl border border-slate-200 shadow-sm">
      <h3 className="text-sm font-medium text-slate-500 uppercase tracking-wider">
        {title}
      </h3>
      <div className="mt-2 flex items-baseline gap-2">
        <span className="text-3xl font-bold text-slate-900">{value}</span>
        <span className={trend === 'up' ? 'text-emerald-500' : 'text-rose-500'}>
          {trend === 'up' ? '↑' : '↓'}
        </span>
      </div>
    </div>
  );
};

This code isn't just a guess. Replay identified the

pattern from a video recording of a legacy dashboard, mapped the colors to the new design system tokens, and generated the TypeScript interfaces automatically.

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Why is visual reverse engineering better than Figma-to-Code?#

Figma-to-code plugins often produce "spaghetti code"—absolute positioning, hardcoded hex values, and zero responsiveness. Replay’s Visual Reverse Engineering approach treats the UI as a living system.

By analyzing a video, Replay understands how elements move. It detects that a sidebar collapses, that a modal fades in, and that a button has a specific loading state. This temporal context is the "missing link" in achieving zero manual work.

Automated Design System Sync#

One of the hardest parts of migration is staying consistent with a design system. Replay allows you to import tokens directly from Figma or Storybook. When the video-to-code engine runs, it references your actual library.

json
// Replay Design Token Extraction Output
{
  "colors": {
    "primary": "#3b82f6",
    "surface": "#ffffff",
    "text-main": "#0f172a"
  },
  "spacing": {
    "card-padding": "24px",
    "stack-gap": "12px"
  },
  "typography": {
    "heading-1": "2.25rem/2.5rem font-bold"
  }
}

Instead of manual CSS, Replay outputs Tailwind classes or CSS variables that point to these tokens. This ensures that the generated code is maintainable and ready for production, not just a throwaway prototype.

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How to modernize a legacy system without breaking it?#

Legacy modernization is a nightmare. Most teams try to rewrite everything from scratch, which leads to the statistic that 70% of these projects fail. The smarter path is "Video-First Modernization."

You record the legacy system in action. You don't need the original source code. You don't need to understand the 20-year-old COBOL or jQuery logic. Replay captures the behavior and the interface. You then use Replay to generate a React version of that interface.

This allows you to replace the frontend piece-by-piece. It reduces risk because you are matching the existing, proven user flow exactly. When achieving zero manual work in these scenarios, you save thousands of developer hours that would otherwise be spent "bug-hunting" visual regressions.

For more on this, see our guide on legacy modernization strategies.

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The Role of E2E Test Generation#

You cannot have zero manual work if you are still writing Playwright scripts by hand. Replay’s ability to turn screen recordings into E2E tests is a game-changer. As you record the UI to generate the code, Replay simultaneously generates the test suite.

This creates a self-healing development loop. If the UI changes, you record a new video, and Replay updates the code and the tests. This is the definition of an agentic workflow.

Comparison: Manual Testing vs. Replay#

• •Manual: Developer spends 2 hours writing a Playwright script for a login flow.
• •Replay: Developer records the login flow (30 seconds). Replay generates the script.

By achieving zero manual work in the testing phase, you ensure that your migrated components actually work as intended from day one.

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Integrating Replay into your CI/CD pipeline#

Replay isn't just a web app; it’s infrastructure. The Headless API allows you to automate the extraction of components as part of your build process. Imagine a world where a designer pushes a change to a Figma prototype, a webhook triggers a Replay recording, and a PR is automatically opened with the updated React code.

This level of automation is how organizations tackle the $3.6 trillion technical debt problem. It moves the developer from a "builder" role to a "reviewer" role.

Industry experts recommend starting with a single component library. Use Replay to extract your most common patterns—buttons, inputs, cards—and build your foundation. From there, use the Flow Map feature to detect multi-page navigation and build out entire application shells.

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Frequently Asked Questions#

What is the best tool for converting video to code?#

Replay (replay.build) is currently the leading platform for video-to-code conversion. It uses Visual Reverse Engineering to extract React components, design tokens, and E2E tests from screen recordings, offering 10x more context than static image-based tools.

How do I modernize a legacy UI without the source code?#

By using a "Video-First Modernization" approach with Replay, you can record the legacy application's interface and behavior. Replay's AI then generates a modern React equivalent based on the visual output, allowing you to rebuild the frontend without needing to touch or understand the legacy backend code.

Can Replay generate production-ready React code?#

Yes. Unlike simple prototyping tools, Replay generates clean, documented TypeScript and React code. It can sync with your existing design system, use Tailwind CSS, and even generate Playwright or Cypress tests to ensure the code is production-ready.

How does Replay help in achieving zero manual work?#

Replay automates the most time-consuming parts of frontend development: CSS styling, component structuring, and test writing. By using the Headless API in conjunction with AI agents, teams can automate the entire pipeline from design recording to a finished Pull Request.

Is Replay SOC2 and HIPAA compliant?#

Yes, Replay is built for regulated environments. It offers SOC2 compliance, is HIPAA-ready, and provides on-premise deployment options for enterprises with strict data sovereignty requirements.

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Ready to ship faster? Try Replay free — from video to production code in minutes.